From: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> Sent: Monday, November 11, 2024 5:13 AM
>
> It was found that unloading 'hid_hyperv' module results in a devres
> complaint:
>
> ...
> hv_vmbus: unregistering driver hid_hyperv
> ------------[ cut here ]------------
> WARNING: CPU: 2 PID: 3983 at drivers/base/devres.c:691
> devres_release_group+0x1f2/0x2c0
> ...
> Call Trace:
> <TASK>
> ? devres_release_group+0x1f2/0x2c0
> ? __warn+0xd1/0x1c0
> ? devres_release_group+0x1f2/0x2c0
> ? report_bug+0x32a/0x3c0
> ? handle_bug+0x53/0xa0
> ? exc_invalid_op+0x18/0x50
> ? asm_exc_invalid_op+0x1a/0x20
> ? devres_release_group+0x1f2/0x2c0
> ? devres_release_group+0x90/0x2c0
> ? rcu_is_watching+0x15/0xb0
> ? __pfx_devres_release_group+0x10/0x10
> hid_device_remove+0xf5/0x220
> device_release_driver_internal+0x371/0x540
> ? klist_put+0xf3/0x170
> bus_remove_device+0x1f1/0x3f0
> device_del+0x33f/0x8c0
> ? __pfx_device_del+0x10/0x10
> ? cleanup_srcu_struct+0x337/0x500
> hid_destroy_device+0xc8/0x130
> mousevsc_remove+0xd2/0x1d0 [hid_hyperv]
> device_release_driver_internal+0x371/0x540
> driver_detach+0xc5/0x180
> bus_remove_driver+0x11e/0x2a0
> ? __mutex_unlock_slowpath+0x160/0x5e0
> vmbus_driver_unregister+0x62/0x2b0 [hv_vmbus]
> ...
>
> And the issue seems to be that the corresponding devres group is not
> allocated. Normally, devres_open_group() is called from
> __hid_device_probe() but Hyper-V HID driver overrides 'hid_dev->driver'
> with 'mousevsc_hid_driver' stub and basically re-implements
> __hid_device_probe() by calling hid_parse() and hid_hw_start() but not
> devres_open_group(). hid_device_probe() does not call __hid_device_probe()
> for it. Later, when the driver is removed, hid_device_remove() calls
> devres_release_group() as it doesn't check whether hdev->driver was
> initially overridden or not.
>
> The issue seems to be related to the commit 62c68e7cee33 ("HID: ensure
> timely release of driver-allocated resources") but the commit itself seems
> to be correct.
>
> Fix the issue by dropping the 'hid_dev->driver' override and using
> hid_register_driver()/hid_unregister_driver() instead. Alternatively, it
> would have been possible to rely on the default handling but
> HID_CONNECT_DEFAULT implies HID_CONNECT_HIDRAW and it doesn't seem to work
> for mousevsc as-is.
>
> Fixes: 62c68e7cee33 ("HID: ensure timely release of driver-allocated resources")
> Suggested-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> ---
> Changes since v1:
> - Keep custom HID driver for mousevsc but do it properly
> [Michael Kelley].
> - Add 'Fixes:' tag [Saurabh Singh Sengar].
> ---
> drivers/hid/hid-hyperv.c | 58 ++++++++++++++++++++++++++++------------
> 1 file changed, 41 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/hid/hid-hyperv.c b/drivers/hid/hid-hyperv.c
> index f33485d83d24..0fb210e40a41 100644
> --- a/drivers/hid/hid-hyperv.c
> +++ b/drivers/hid/hid-hyperv.c
> @@ -422,6 +422,25 @@ static int mousevsc_hid_raw_request(struct hid_device *hid,
> return 0;
> }
>
> +static int mousevsc_hid_probe(struct hid_device *hid_dev, const struct hid_device_id *id)
> +{
> + int ret;
> +
> + ret = hid_parse(hid_dev);
> + if (ret) {
> + hid_err(hid_dev, "parse failed\n");
> + return ret;
> + }
> +
> + ret = hid_hw_start(hid_dev, HID_CONNECT_HIDINPUT | HID_CONNECT_HIDDEV);
> + if (ret) {
> + hid_err(hid_dev, "hw start failed\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> static const struct hid_ll_driver mousevsc_ll_driver = {
> .parse = mousevsc_hid_parse,
> .open = mousevsc_hid_open,
> @@ -431,7 +450,16 @@ static const struct hid_ll_driver mousevsc_ll_driver = {
> .raw_request = mousevsc_hid_raw_request,
> };
>
> -static struct hid_driver mousevsc_hid_driver;
> +static const struct hid_device_id mousevsc_devices[] = {
> + { HID_DEVICE(BUS_VIRTUAL, HID_GROUP_ANY, 0x045E, 0x0621) },
> + { }
> +};
> +
> +static struct hid_driver mousevsc_hid_driver = {
> + .name = "hid-hyperv",
> + .id_table = mousevsc_devices,
> + .probe = mousevsc_hid_probe,
> +};
>
> static int mousevsc_probe(struct hv_device *device,
> const struct hv_vmbus_device_id *dev_id)
> @@ -473,7 +501,6 @@ static int mousevsc_probe(struct hv_device *device,
> }
>
> hid_dev->ll_driver = &mousevsc_ll_driver;
> - hid_dev->driver = &mousevsc_hid_driver;
> hid_dev->bus = BUS_VIRTUAL;
> hid_dev->vendor = input_dev->hid_dev_info.vendor;
> hid_dev->product = input_dev->hid_dev_info.product;
> @@ -488,20 +515,6 @@ static int mousevsc_probe(struct hv_device *device,
> if (ret)
> goto probe_err2;
>
> -
> - ret = hid_parse(hid_dev);
> - if (ret) {
> - hid_err(hid_dev, "parse failed\n");
> - goto probe_err2;
> - }
> -
> - ret = hid_hw_start(hid_dev, HID_CONNECT_HIDINPUT | HID_CONNECT_HIDDEV);
> -
> - if (ret) {
> - hid_err(hid_dev, "hw start failed\n");
> - goto probe_err2;
> - }
> -
> device_init_wakeup(&device->device, true);
>
> input_dev->connected = true;
> @@ -579,12 +592,23 @@ static struct hv_driver mousevsc_drv = {
>
> static int __init mousevsc_init(void)
> {
> - return vmbus_driver_register(&mousevsc_drv);
> + int ret;
> +
> + ret = hid_register_driver(&mousevsc_hid_driver);
> + if (ret)
> + return ret;
> +
> + ret = vmbus_driver_register(&mousevsc_drv);
> + if (ret)
> + hid_unregister_driver(&mousevsc_hid_driver);
> +
> + return ret;
> }
>
> static void __exit mousevsc_exit(void)
> {
> vmbus_driver_unregister(&mousevsc_drv);
> + hid_unregister_driver(&mousevsc_hid_driver);
> }
>
> MODULE_LICENSE("GPL");
> --
> 2.47.0
Reviewed-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
